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XL6 milling yield improves in bin

Elton Robinson | Mar 23, 2001

Several Arkansas producers who stored their XL6 rice on-farm in 2000-01 had a pleasant surprise when they checked their final milling yield — it had gone up significantly.

Delaplane, Ark., producer Terry Gray grew about 60 acres of XL6 in 2000. His first milling yield sample, taken at harvest, came in at 44/67. “That was around the middle of September. I put the rice in the bins and dried it mostly with air and a little bit of heat. It's what a lot of the oldtimers call tempering. I guess when it sits in that bin awhile, it gets a chance to cure out.”

Gray held the rice in the bin until March. When the milling yield was checked again, it had improved to a 58/68 on about 13,000 bushels.

Wynne, Ark., rice producer Bryan Moery reported that his milling yield on XL6 improved from 34/62 right after harvest to 44/66 after several weeks in the bin. “We kept some in the bin until around Dec. 1 and we got a 47/67 and a 65/71.”

According to RiceTec, the company that developed hybrid rice technology for the United States, XL6 farmers reported milling yield improvements in head rice (from 7 to 15 points) after tempering XL6 grain in on-farm storage from two weeks to four months. Average gains last year from the improvement in milling yield were 13 to 15 cents per bushel.

“The recommendation we hear most often for drying, is the use of high volumes of ambient air, very low heat and minimize stirring,” said Jim Thompson, RiceTec's national sales manager.

While Moery will again plant XL6 and another experimental hybrid this year, he still isn't convinced that XL6 will consistently yield 20 to 25 bushels more than Cocodrie and his other varieties. “I don't have all my yield data in yet, but I don't know if it's going to work out or not. I believe they're going to need a better variety than XL6. They're going to have to work on the lodging.”

On the other hand, Gray was very happy with his yields of XL6. “Our farm averages anywhere from 160 to 165 bushels dry on a good year. We cut 215 bushels an acre on the XL6.”

XL6 is the first hybrid rice to be released commercially in the United States. It will be available through local dealerships this spring, according to RiceTec.

Hybrid rice has more seedling vigor and yields higher than varietal rice. However, XL6 growers have observed lower milling yields and lodging under certain situations. For that reason, XL6 — but not necessarily all rice hybrids — requires special management practices.

For example, recommended seeding and fertilizer rates for XL6 are slashed to less than half of non-hybrids. While the reduced seeding rate is almost immediately compensated for by good seed germination and vigorous tillering, the plant's pale color during the season gives the impression that's it's under-fertilized.

XL6 yields about 40 to 45 bushels more than the average of varietal rice, according to the company, which more than offsets the higher seed costs and frequent problem of lower milling yields in XL6.

A good fertility program is also important for XL6. According to the company, any nutrient shortage detected by soil tests should be corrected with appropriate preplant fertilizer.

Previous research has demonstrated that adequate potassium supply often improves straw strength and delays leaf senescence , according to John Nelson, general manager, RiceTec Seed. “Very high-yielding rice varieties and hybrids in particular need more potassium,”

In one replicated trial in northeast Arkansas in 2000, a preplant application of 200 pounds of potassium to XL6 growing on a sandy loam soil (testing barely under the level for recommending 60 pounds) resulted in 7-hundredweight yield increase, no lodging, and an improvement in head rice from 44 to 63 percent.

Potassium is known to be readily preserved in the soil. Any carryover of potassium applied to rice will benefit the next crop in a rotation, especially soybeans, the company noted.

Limited company and university data suggests that up to 60 units of nitrogen applied at 5 percent heading may increase grain and milling yields while decreasing lodging. The company's replicated trial showed no additional benefit with heading nitrogen if the high potassium program was used earlier.

If you're thinking about planting XL6 this year, here is a recipe for success. This protocol is specifically for XL6. Future rice hybrids from RiceTec may require different management practices:

Select fields with no history of straighthead.

Best soil type for XL6 is silt loam, followed by clay, then sand.

Soil test and apply nutrients as required.

Adjust grain drill prior to planting to 35 pounds per acre. Use large sprockets to reduce drive speed and open seed-feeder wide to avoid grinding seed.

Plant into a stale or conventional seedbed.

Plant XL6 first between April 1 and April 25 when soil temperature reaches 65 degrees at 1 inch. (Early planting reduces lodging potential.)

Drill at normal depth, checking to be sure drill furrow is closing and seed is covered.

Check seeding rate regularly and adjust as needed (a seeding rate chart for seeds per row foot is on the XL6 bag).

Apply 60 units of nitrogen (133 pounds of urea) by air or ground pre-flood and flood entire field within five days. Discuss any and all planned adjustments to nitrogen rate for soil type, previous crop, straight head, etc., with your RiceTec technical service representative.

Monitor XL6 fields for disease and late-season insect pressure and take necessary steps (no XL6 field in 1999 or 2000 required a fungicide treatment).

Maintain a flood (unless drained for straighthead) until the normal draining period for your soil type and conditions.

XL6 dries down quickly and is often drier than it appears; monitor moisture carefully and harvest XL6 between 18 and 21 percent moisture on the first dry down. Store XL6 on farm to increase milling yields; drying with high volumes of ambient air and very low heat (105 degrees).